Germany's cities have for years flouted Europe's clean air rules, prompting environmental groups to sue local governments in an attempt to force bans of some heavily polluting vehicles. The first diesel ban took effect in May in Hamburg.

The government outlined plans earlier this month to cut pollution from diesel vehicles by asking carmakers to offer owners trade-in incentives and hardware fixes in an attempt to avert driving bans in major cities such as Berlin and Hamburg.

As per the suit filed, Royal Enfield has infringed Flash electronics’ patent on “Regulator Rectifier Device and Method for Regulating an Output Voltage of the Same” duly issued by the United States Patent & Trademark Office (USPTO) to Flash Electronics on February 20, 2018 after Flash’s R&D department made a breakthrough invention of the component in 2014.